Oligosaccharides are being increasingly identified with the biological activities. Chitooligosaccharides (COS), a type of specifically alkali oligosaccharides prepared by chemical and enzymatic hydrolysis of chitosan, was found to have antimicrobial, antibacterial, antitumour and antiangiogenesis properties [1]. But the biological screening is usually performed by using mixture of COS with different degree of polymerization [2], which is an unfavorable way to discover exactly active compounds. Separation and purification of COS is quite difficult due to the highly polarity. A new technique for purification of COS with high efficiency was developed by using purification factory, which is a 4-channel parallel preparative high performance liquid chromatography (HPLC) system. Hydrophilic interaction chromatography (HILIC), an effective HPLC mode for separation of very polar compounds including oligosaccharides [3], was employed to obtain enough retention and resolution of COS under optimized conditions. Four fractions were collected by using mass spectrometry (MS) as collection trigger. The four fractions are four kinds of COS with different degree of polymerization, which is 2, 3, 4, 5, respectively. This new purification technique, together with the purified products, will be very helpful to the research on oligosaccharides.
References:
[1] Chung, Y. C., Kuo, C. L. and Chen, C. C. 2005. Preparation and important functional properties of water-soluble chitosan produced through Maillard reaction. Bioresource Technology, 13, 1473-1482.
[2] Dou, J. L., Tan, C. Y., Du, Y. G., Bai, X. F., Wang, K. Y. and Ma, X. J. 2007. Effects of chitooligosaccharides on rabbit neutrophils in vitro. Carbohydrate Polymers, 69, 209-213.
[3] Hemstrom, P. and Irgum, K. 2006. Hydrophilic interaction chromatography. Journal of Separation Science, 29, 1784-1821.